Feb/19/2008

1. A Demography of Galaxies in Galaxy Clusters with the Spectro-photometric Density Measurement. Feb/19/2008 Dept. of Astronomy Yonsei Univ. Joo Heon Yoon 윤주헌 Sukyoung Yi 이석영 Yoon et al. 2008 ApJS in press (astro-ph/0712.1054)

2. I. Motivation II. Method III. Result Environment Effect J. H. Yoon K. Schawinski S. K. Yi • Check individual clusters of galaxies. • Require homogeneous catalogue.

3. I. Motivation II. Method III. Result Incompleteness of Spectroscopy • Classical cluster catalogue (e.g. Abell) • Based on eye-inspection. • Projection effect, time-consuming… • Massive database (SDSS, 2dF, …) • Systematic Search! • Redshift – 3D distribution! (e.g. C4) Incompleteness Problem!! Fiber collision!! Spectroscopy is incomplete!! In a dense cluster, fspec. ~ 65%

4. I. Motivation II. Method III. Result Data • SDSS DR5 spectroscopic and photometric survey galaxies. • 0.05 < z < 0.1 • Volume limited samples, r<17.77, Mr < -20.54

5. I. Motivation II. Method III. Result Cluster Member Selection via CMR How do we add galaxies missed by spectroscopic survey?  Galaxies in a cluster have Color-Magnitude Relation.

6. Measure local density of galaxies where 3σ=1Mpc, and σv = velocity dispersion Select red-sequence galaxies in CMR spectro-photometric density I. Motivation II. Method III. Result Cluster Finding with spec.+phot. data For galaxies with spectra. For galaxies without spectra. Finding the Maximum Density Galaxy!!  Finding Galaxy Cluster!!

7. I. Motivation II. Method III. Result Cluster Finding with spec.+phot. data Yoon, Schawinski, Sheen, Ree, & Yi, 2008 ApJS in Press (astro-ph/0712.1054) From SDSS

8. New density Spec. density CTIO density I. Motivation II. Method III. Result Efficiency of the New Measurement A2670 missing Our new method.  Minimize the incompleteness. CTIO observation supports our method. 92% of completeness by CTIO obs. From SDSS

9. I. Motivation II. Method III. Result Galaxy Classification • Consider spectroscopic members • Visual Inspection • SDSS optical combined images • Self-consistency • fracdev_r • Color Classification • Non-cluster Galaxies • ρ = 0 From SDSS

10. I. Motivation II. Method III. Result Color & Luminosity vs. Radius • Color & Luminosity • No clustocentric dependence. From SDSS

11. I. Motivation II. Method III. Result Color & Luminosity vs. Radius • Color & Morphology • Clustocentric dependence < R200 • MDR is intrisic. • The morphology-density relation  Stronger in Denser cluster From SDSS

12. I. Motivation II. Method III. Result Why the Brightest Cluster Galaxy? BCGs in simulation • Extremely huge • Continuously growing • BCGs are so special. • von der Linden et al. 2007 : BCG & non-BCG difference • Liu et al. 2007 : Different scaling relations. • Quillen et al. 2007 : Star formation in BCGs.  Secondary of environmental effect? From SDSS

13. I. Motivation II. Method III. Result The BCGs vs. Density • Denser  Brighter BCGs As well as 2nd BCGs & 3rd BCGs • No difference in their density dependence. From SDSS

14. I. Motivation II. Method III. Result The BCGs vs. NCGs • BCGs, 2nd BCGs, & 3rd BCGs are redder than Non-cluster galaxies. • They are different population. From SDSS

15. I. Motivation II. Method III. Result CMR of ETGs • Cluster ETGs are optically red. • Non-cluster ETGs have a blue tail. From SDSS

16. Gomez et al. 2003 I. Motivation II. Method III. Result Environmental Dependence From SDSS

17. I. Motivation II. Method III. Result Environmental Dependence From SDSS

18. Local density effect on galaxy colors Galaxy position in clusters > I. Motivation II. Method III. Result ρ vs. Rclustocentric g - r g - r Red/Blue Red/Blue R/R200 R/R200 From SDSS ρ ρ

19. Conclusion • New density measurement. • minimize the incompleteness. • A better tool for environment study. • New homogenous cluster catalogue. • Color radial dependence  Morphology-Density relation. • Denser Environment  Stronger MDR • Denser Brighter BCGs • Cluster Galaxies Redder than Non-cluster Galaxies. They are different each other. • BCGs and other cluster galaxies.  show the same Mr-density relation. • Local galaxy density > Position in cluster • New density measurement. • minimize the incompleteness. • A better tool for environment study. • New homogenous cluster catalogue. • Color radial dependence  Morphology-Density relation. • Denser Environment  Stronger MDR • Denser  Brighter BCGs • Cluster Galaxies Redder than Non-cluster Galaxies. They are different each other. • BCGs and other cluster galaxies.  show the same Mr-density relation. • Local galaxy density > Position in cluster

20. All color logos

21. All color logos

22. All color logos

23. DEC RA z DEC RA z 3 Xσv 1Mpc Line of Sight I. Motivation II. Method III. Result Measuring Density (Schawinski et al. 2006)

24. I. Motivation II. Method III. Result A Demography of Cluster Galaxies From SDSS

25. I. Motivation II. Method III. Result Efficiency of the New Measurement BCGs are generally in centers. BCG & MDG separation smaller, better. From SDSS

26. I. Motivation II. Method III. Result Efficiency of the New Measurement CMR efficiency test with spectroscopic, early-type (fracdev_r > 0.95) member galaxies. Completeness = Purity = 90% cover 15% contamination From SDSS

29. I. Motivation II. Method III. Result Efficiency of the New Measurement Our new density parameter  Good tracer of cluster size and mass. From SDSS

30. Future Study • Spectrum analysis  Line indices, SFR, etc. ― Clustocentric radius • SH’s SAM clusters with Khochfar’s semi-analytical model vs. Observed clusters  Constrain SAM. From SDSS